Heroic mode? It's incredibly important. It's 7,000,000 per person who does the dance full time. The tanks alone are 14,000,000 damage. Add you on, that's 21,000,000 hp you simply can ignore.
The dance is very easy, ignore his animation - they're very misleading unless you know them well. Watch the blue lines. The first line comes out about a quarter of a second before he finishes his animation anyways. ALWAYS run DIRECTLY into the boss the SECOND the dance starts. Always. The second you see the blue line - Avoid it. Just remember, the AoE is beyond the boss. If his slash is left, the slash STARTS about 5 yards RIGHT of the boss.
The stomp is the only thing I've been hit by since our first attempt. Only got hit by that twice, in dozens of attempts. Just gotta be quick. Be sure to not move more than 18 yards from the boss. The stomp aoe vs the magnetic pull range is only a 3 yard gap - that's all that makes stomp a pain.